1 /* Sign a module file using the given key. 2 * 3 * Copyright © 2014-2016 Red Hat, Inc. All Rights Reserved. 4 * Copyright © 2015 Intel Corporation. 5 * Copyright © 2016 Hewlett Packard Enterprise Development LP 6 * 7 * Authors: David Howells <dhowells@redhat.com> 8 * David Woodhouse <dwmw2@infradead.org> 9 * Juerg Haefliger <juerg.haefliger@hpe.com> 10 * 11 * This program is free software; you can redistribute it and/or 12 * modify it under the terms of the GNU Lesser General Public License 13 * as published by the Free Software Foundation; either version 2.1 14 * of the licence, or (at your option) any later version. 15 */ 16 #define _GNU_SOURCE 17 #include <stdio.h> 18 #include <stdlib.h> 19 #include <stdint.h> 20 #include <stdbool.h> 21 #include <string.h> 22 #include <getopt.h> 23 #include <err.h> 24 #include <arpa/inet.h> 25 #include <openssl/opensslv.h> 26 #include <openssl/bio.h> 27 #include <openssl/evp.h> 28 #include <openssl/pem.h> 29 #include <openssl/err.h> 30 #include <openssl/engine.h> 31 32 /* 33 * Use CMS if we have openssl-1.0.0 or newer available - otherwise we have to 34 * assume that it's not available and its header file is missing and that we 35 * should use PKCS#7 instead. Switching to the older PKCS#7 format restricts 36 * the options we have on specifying the X.509 certificate we want. 37 * 38 * Further, older versions of OpenSSL don't support manually adding signers to 39 * the PKCS#7 message so have to accept that we get a certificate included in 40 * the signature message. Nor do such older versions of OpenSSL support 41 * signing with anything other than SHA1 - so we're stuck with that if such is 42 * the case. 43 */ 44 #if defined(LIBRESSL_VERSION_NUMBER) || \ 45 OPENSSL_VERSION_NUMBER < 0x10000000L || \ 46 defined(OPENSSL_NO_CMS) 47 #define USE_PKCS7 48 #endif 49 #ifndef USE_PKCS7 50 #include <openssl/cms.h> 51 #else 52 #include <openssl/pkcs7.h> 53 #endif 54 55 struct module_signature { 56 uint8_t algo; /* Public-key crypto algorithm [0] */ 57 uint8_t hash; /* Digest algorithm [0] */ 58 uint8_t id_type; /* Key identifier type [PKEY_ID_PKCS7] */ 59 uint8_t signer_len; /* Length of signer's name [0] */ 60 uint8_t key_id_len; /* Length of key identifier [0] */ 61 uint8_t __pad[3]; 62 uint32_t sig_len; /* Length of signature data */ 63 }; 64 65 #define PKEY_ID_PKCS7 2 66 67 static char magic_number[] = "~Module signature appended~\n"; 68 69 static __attribute__((noreturn)) 70 void format(void) 71 { 72 fprintf(stderr, 73 "Usage: scripts/sign-file [-dp] <hash algo> <key> <x509> <module> [<dest>]\n"); 74 fprintf(stderr, 75 " scripts/sign-file -s <raw sig> <hash algo> <x509> <module> [<dest>]\n"); 76 exit(2); 77 } 78 79 static void display_openssl_errors(int l) 80 { 81 const char *file; 82 char buf[120]; 83 int e, line; 84 85 if (ERR_peek_error() == 0) 86 return; 87 fprintf(stderr, "At main.c:%d:\n", l); 88 89 while ((e = ERR_get_error_line(&file, &line))) { 90 ERR_error_string(e, buf); 91 fprintf(stderr, "- SSL %s: %s:%d\n", buf, file, line); 92 } 93 } 94 95 static void drain_openssl_errors(void) 96 { 97 const char *file; 98 int line; 99 100 if (ERR_peek_error() == 0) 101 return; 102 while (ERR_get_error_line(&file, &line)) {} 103 } 104 105 #define ERR(cond, fmt, ...) \ 106 do { \ 107 bool __cond = (cond); \ 108 display_openssl_errors(__LINE__); \ 109 if (__cond) { \ 110 err(1, fmt, ## __VA_ARGS__); \ 111 } \ 112 } while(0) 113 114 static const char *key_pass; 115 116 static int pem_pw_cb(char *buf, int len, int w, void *v) 117 { 118 int pwlen; 119 120 if (!key_pass) 121 return -1; 122 123 pwlen = strlen(key_pass); 124 if (pwlen >= len) 125 return -1; 126 127 strcpy(buf, key_pass); 128 129 /* If it's wrong, don't keep trying it. */ 130 key_pass = NULL; 131 132 return pwlen; 133 } 134 135 static EVP_PKEY *read_private_key(const char *private_key_name) 136 { 137 EVP_PKEY *private_key; 138 139 if (!strncmp(private_key_name, "pkcs11:", 7)) { 140 ENGINE *e; 141 142 ENGINE_load_builtin_engines(); 143 drain_openssl_errors(); 144 e = ENGINE_by_id("pkcs11"); 145 ERR(!e, "Load PKCS#11 ENGINE"); 146 if (ENGINE_init(e)) 147 drain_openssl_errors(); 148 else 149 ERR(1, "ENGINE_init"); 150 if (key_pass) 151 ERR(!ENGINE_ctrl_cmd_string(e, "PIN", key_pass, 0), 152 "Set PKCS#11 PIN"); 153 private_key = ENGINE_load_private_key(e, private_key_name, 154 NULL, NULL); 155 ERR(!private_key, "%s", private_key_name); 156 } else { 157 BIO *b; 158 159 b = BIO_new_file(private_key_name, "rb"); 160 ERR(!b, "%s", private_key_name); 161 private_key = PEM_read_bio_PrivateKey(b, NULL, pem_pw_cb, 162 NULL); 163 ERR(!private_key, "%s", private_key_name); 164 BIO_free(b); 165 } 166 167 return private_key; 168 } 169 170 static X509 *read_x509(const char *x509_name) 171 { 172 unsigned char buf[2]; 173 X509 *x509; 174 BIO *b; 175 int n; 176 177 b = BIO_new_file(x509_name, "rb"); 178 ERR(!b, "%s", x509_name); 179 180 /* Look at the first two bytes of the file to determine the encoding */ 181 n = BIO_read(b, buf, 2); 182 if (n != 2) { 183 if (BIO_should_retry(b)) { 184 fprintf(stderr, "%s: Read wanted retry\n", x509_name); 185 exit(1); 186 } 187 if (n >= 0) { 188 fprintf(stderr, "%s: Short read\n", x509_name); 189 exit(1); 190 } 191 ERR(1, "%s", x509_name); 192 } 193 194 ERR(BIO_reset(b) != 0, "%s", x509_name); 195 196 if (buf[0] == 0x30 && buf[1] >= 0x81 && buf[1] <= 0x84) 197 /* Assume raw DER encoded X.509 */ 198 x509 = d2i_X509_bio(b, NULL); 199 else 200 /* Assume PEM encoded X.509 */ 201 x509 = PEM_read_bio_X509(b, NULL, NULL, NULL); 202 203 BIO_free(b); 204 ERR(!x509, "%s", x509_name); 205 206 return x509; 207 } 208 209 int main(int argc, char **argv) 210 { 211 struct module_signature sig_info = { .id_type = PKEY_ID_PKCS7 }; 212 char *hash_algo = NULL; 213 char *private_key_name = NULL, *raw_sig_name = NULL; 214 char *x509_name, *module_name, *dest_name; 215 bool save_sig = false, replace_orig; 216 bool sign_only = false; 217 bool raw_sig = false; 218 unsigned char buf[4096]; 219 unsigned long module_size, sig_size; 220 unsigned int use_signed_attrs; 221 const EVP_MD *digest_algo; 222 EVP_PKEY *private_key; 223 #ifndef USE_PKCS7 224 CMS_ContentInfo *cms = NULL; 225 unsigned int use_keyid = 0; 226 #else 227 PKCS7 *pkcs7 = NULL; 228 #endif 229 X509 *x509; 230 BIO *bd, *bm; 231 int opt, n; 232 OpenSSL_add_all_algorithms(); 233 ERR_load_crypto_strings(); 234 ERR_clear_error(); 235 236 key_pass = getenv("KBUILD_SIGN_PIN"); 237 238 #ifndef USE_PKCS7 239 use_signed_attrs = CMS_NOATTR; 240 #else 241 use_signed_attrs = PKCS7_NOATTR; 242 #endif 243 244 do { 245 opt = getopt(argc, argv, "sdpk"); 246 switch (opt) { 247 case 's': raw_sig = true; break; 248 case 'p': save_sig = true; break; 249 case 'd': sign_only = true; save_sig = true; break; 250 #ifndef USE_PKCS7 251 case 'k': use_keyid = CMS_USE_KEYID; break; 252 #endif 253 case -1: break; 254 default: format(); 255 } 256 } while (opt != -1); 257 258 argc -= optind; 259 argv += optind; 260 if (argc < 4 || argc > 5) 261 format(); 262 263 if (raw_sig) { 264 raw_sig_name = argv[0]; 265 hash_algo = argv[1]; 266 } else { 267 hash_algo = argv[0]; 268 private_key_name = argv[1]; 269 } 270 x509_name = argv[2]; 271 module_name = argv[3]; 272 if (argc == 5 && strcmp(argv[3], argv[4]) != 0) { 273 dest_name = argv[4]; 274 replace_orig = false; 275 } else { 276 ERR(asprintf(&dest_name, "%s.~signed~", module_name) < 0, 277 "asprintf"); 278 replace_orig = true; 279 } 280 281 #ifdef USE_PKCS7 282 if (strcmp(hash_algo, "sha1") != 0) { 283 fprintf(stderr, "sign-file: %s only supports SHA1 signing\n", 284 OPENSSL_VERSION_TEXT); 285 exit(3); 286 } 287 #endif 288 289 /* Open the module file */ 290 bm = BIO_new_file(module_name, "rb"); 291 ERR(!bm, "%s", module_name); 292 293 if (!raw_sig) { 294 /* Read the private key and the X.509 cert the PKCS#7 message 295 * will point to. 296 */ 297 private_key = read_private_key(private_key_name); 298 x509 = read_x509(x509_name); 299 300 /* Digest the module data. */ 301 OpenSSL_add_all_digests(); 302 display_openssl_errors(__LINE__); 303 digest_algo = EVP_get_digestbyname(hash_algo); 304 ERR(!digest_algo, "EVP_get_digestbyname"); 305 306 #ifndef USE_PKCS7 307 /* Load the signature message from the digest buffer. */ 308 cms = CMS_sign(NULL, NULL, NULL, NULL, 309 CMS_NOCERTS | CMS_PARTIAL | CMS_BINARY | 310 CMS_DETACHED | CMS_STREAM); 311 ERR(!cms, "CMS_sign"); 312 313 ERR(!CMS_add1_signer(cms, x509, private_key, digest_algo, 314 CMS_NOCERTS | CMS_BINARY | 315 CMS_NOSMIMECAP | use_keyid | 316 use_signed_attrs), 317 "CMS_add1_signer"); 318 ERR(CMS_final(cms, bm, NULL, CMS_NOCERTS | CMS_BINARY) < 0, 319 "CMS_final"); 320 321 #else 322 pkcs7 = PKCS7_sign(x509, private_key, NULL, bm, 323 PKCS7_NOCERTS | PKCS7_BINARY | 324 PKCS7_DETACHED | use_signed_attrs); 325 ERR(!pkcs7, "PKCS7_sign"); 326 #endif 327 328 if (save_sig) { 329 char *sig_file_name; 330 BIO *b; 331 332 ERR(asprintf(&sig_file_name, "%s.p7s", module_name) < 0, 333 "asprintf"); 334 b = BIO_new_file(sig_file_name, "wb"); 335 ERR(!b, "%s", sig_file_name); 336 #ifndef USE_PKCS7 337 ERR(i2d_CMS_bio_stream(b, cms, NULL, 0) < 0, 338 "%s", sig_file_name); 339 #else 340 ERR(i2d_PKCS7_bio(b, pkcs7) < 0, 341 "%s", sig_file_name); 342 #endif 343 BIO_free(b); 344 } 345 346 if (sign_only) { 347 BIO_free(bm); 348 return 0; 349 } 350 } 351 352 /* Open the destination file now so that we can shovel the module data 353 * across as we read it. 354 */ 355 bd = BIO_new_file(dest_name, "wb"); 356 ERR(!bd, "%s", dest_name); 357 358 /* Append the marker and the PKCS#7 message to the destination file */ 359 ERR(BIO_reset(bm) < 0, "%s", module_name); 360 while ((n = BIO_read(bm, buf, sizeof(buf))), 361 n > 0) { 362 ERR(BIO_write(bd, buf, n) < 0, "%s", dest_name); 363 } 364 BIO_free(bm); 365 ERR(n < 0, "%s", module_name); 366 module_size = BIO_number_written(bd); 367 368 if (!raw_sig) { 369 #ifndef USE_PKCS7 370 ERR(i2d_CMS_bio_stream(bd, cms, NULL, 0) < 0, "%s", dest_name); 371 #else 372 ERR(i2d_PKCS7_bio(bd, pkcs7) < 0, "%s", dest_name); 373 #endif 374 } else { 375 BIO *b; 376 377 /* Read the raw signature file and write the data to the 378 * destination file 379 */ 380 b = BIO_new_file(raw_sig_name, "rb"); 381 ERR(!b, "%s", raw_sig_name); 382 while ((n = BIO_read(b, buf, sizeof(buf))), n > 0) 383 ERR(BIO_write(bd, buf, n) < 0, "%s", dest_name); 384 BIO_free(b); 385 } 386 387 sig_size = BIO_number_written(bd) - module_size; 388 sig_info.sig_len = htonl(sig_size); 389 ERR(BIO_write(bd, &sig_info, sizeof(sig_info)) < 0, "%s", dest_name); 390 ERR(BIO_write(bd, magic_number, sizeof(magic_number) - 1) < 0, "%s", dest_name); 391 392 ERR(BIO_free(bd) < 0, "%s", dest_name); 393 394 /* Finally, if we're signing in place, replace the original. */ 395 if (replace_orig) 396 ERR(rename(dest_name, module_name) < 0, "%s", dest_name); 397 398 return 0; 399 } 400